Hangs after prefiltering light cache

[timmatron]

I am not sure with what version I started seeing this, but...

If I send out a large resolution still image in strips that is using a saved irradience map and light cache, each strip on every computer will hang for a long time while the status bar says "prefiltering light cache: done". I don't know how long it takes to get past it, but right now my computer is at 15 minutes and Max is still locked up. It's not a big light cache either, only about 1.5mb. The IR map is big though, at 161mb. But this seems to happen whenever we send out a job in strips using saved GI maps - different files, different jobs altogether.

We are on Max9 32, and Vray 1.5 SP1.

[vlado]

Actually, at this point V-Ray is probably loading the irradiance map. If it is a big one, and if many machines try to load it at the same time, there may be delays.

Best regards,
Vlado

[timmatron]

Is there any way to tell if this is the case? Right now I am at minute 45, waiting for the actual rendering to start. I just don't ever remember this taking so long. Could be our network I guess, but still 45 minutes seems a bit extreme.

I guess I can do some testing later to see if a smaller irradience map makes a difference.

Thanks Vlado.

[vlado]

You can look at the V-Ray log file to see what is going on currently.

Best regards,
Vlado

[timmatron]

Ok, I checked the log and it is for sure loading the irradience map. So I open the task manager to see how fast it is loading it, and it looks like its only loading about 1mb per minute. So at 160mb that is going to take 3 hours to load. Now I am going to try loading the maps locally to see what difference that makes.

[timmatron]

Well, when loading the GI maps from the C drive, it just takes a few seconds before it starts rendering. Now, it still doesn't seem normal that it would take our server 3 hours to send the file to 8 or 10 computers does it? Sounds like a technical problem on our end.

[olly]

Was there any further testing done on this?

Cheers,
Olly

[vlado]

I have not been able to reproduce this unfortunately. If you have a scene where this happens, please send it to me at vlado@chaosgroup.com for investigation.

Best regards,
Vlado

[natty]

Hi,

sometimes we get that when we have the lightcache on auto save, saving and loading at the same time.

But this was on rare occasions..

[olly]

When I get a minute I'll send something to you...

Cheers,
Olly

[olly]

I've done a bit more testing on this now and found the following:

A dual socket 2.5 GHz quad core render node calling a locally stored 270mb Irradiance map takes 30s to start rendering after it starts to load the irradiance map (prefiltering light cache "done" in the render progress dialogue).

The same machine takes 1min when the file is called from the server over a Gigabit LAN and it's the only node rendering.

The same machine takes 10mins when the file is called from the server and 12 machines are rendering the same job.

To me these increased load times make sense, when the traffic increases so does the load time.

However where 12 nodes where used and they've finished rendering their frame they all fail with the error "Could not load irradiance map". This is strange because the frames are rendered & saved out correctly, but of course as they failed Backburner starts the frame again...

I've attached the file for further investigation...

Hope that helps,
Olly

[Mediastation]

Hi All,

We had this problem when we first got Vray. With big scenes and a 30 machine render farm, it could take hours to load the irradiance map, and quite often the scene would time out and fail.

My solution was to set up a folder on each render nodes C drive called VrayMaps and use a folder cloning program. You just copy the pre-calculated Irradiance map & Light cache files into a master folder on the server and the cloning program will examine the folder every five minutes and distribute any new files to each nodes VrayMaps folder. When you send renders to the farm, just make sure Vray looks for the IR & LC files in C:/VrayMaps

This technique has worked fine for us but I was wondering if there was a better solution? How do dedicated render farm company's manage it?

Cheers,

Andy

[arobbert]

Hi All,

We had this problem when we first got Vray. With big scenes and a 30 machine render farm, it could take hours to load the irradiance map, and quite often the scene would time out and fail.

My solution was to set up a folder on each render nodes C drive called VrayMaps and use a folder cloning program. You just copy the pre-calculated Irradiance map & Light cache files into a master folder on the server and the cloning program will examine the folder every five minutes and distribute any new files to each nodes VrayMaps folder. When you send renders to the farm, just make sure Vray looks for the IR & LC files in C:/VrayMaps

This technique has worked fine for us but I was wondering if there was a better solution? How do dedicated render farm company's manage it?

Cheers,

Andy

We have this problem as well and this is the solution we use. What program are you using for the cloning?

[Subburb]

you can try "Allway Sync" it's free, simple and easy to use

[olly]

free for personal use only unfortunately...